Near-infrared-activated nanocalorifiers in microcapsules: Vapor bubble generation for in vivo enhanced cancer therapy

Photothermal therapy based on gold nanostructures has been widely investigated as a state-of-the-art noninvasive therapy approach. Because single nanoparticles cannot harvest sufficient energy, self-assemblies of small plasmonic particles into large aggregates are required for enhanced photothermal performance. Self-assembled gold nanorods in lipid bilayer-modified microcapsules are shown to localize at tumor sites, generate vapor bubbles under near-infrared light exposure, and subsequently damage tumor tissues. The polyelectrolyte multilayer enables dense packing of gold nanorods during the assembly process, which leads to the formation of vapor bubbles around the excited capsules. The resulting vapor bubbles achieve a high efficiency of suppressing tumor growth compared to single gold nanorods. In vivo experiments demonstrated the ability of soft-polymer multilayer microcapsules to cross the biological barriers of the body and localize at target tissues. Antitumor bubbles: A photothermal theranostic platform based on biocompatible gold nanorod-assembled capsules was demonstrated with good deformability behavior and behavior similar to red blood cells. The resulting vapor bubbles, induced by a cumulative thermal effect between adjacent gold nanorods, can locally damage tumor cells and enable photothermal therapy with high efficacy compared to single gold nanorods.